Fix constraint for address model (#5076)

* Fix constraint for address model

- Do not handle at database level
- Add a "validate_unique" method to the address model
- Fixes https://github.com/inventree/InvenTree/issues/5070

* Remove unique constraint rule

* Unit test fix

- Adjust unit test around new code

* Further unit test updates

InvenTree/company/migrations/0063_auto_20230502_1956.py

@@ -30,8 +30,4 @@ class Migration(migrations.Migration):
                 ('company', models.ForeignKey(help_text='Select company', on_delete=django.db.models.deletion.CASCADE, related_name='addresses', to='company.company', verbose_name='Company')),
             ],
         ),
-        migrations.AddConstraint(
-            model_name='address',
-            constraint=models.UniqueConstraint(condition=models.Q(('primary', True)), fields=('company',), name='one_primary_per_company'),
-        ),
     ]